#include <stdio.h>
//判断闰年
void main ()
{
    int year;
    printf("please enter a year:");
    scanf("%d",&year);
    if (year%400==0 || (year %400 ==0 && year %100 != 0 ))
    {
        printf("%d is a leap year!",year);
    }
    else
    printf("%d is not a leap year.",year);
}